// Numbas version: exam_results_page_options {"name": "Daniel's copy of Quantifiers 3-", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"variable_groups": [{"variables": ["select"], "name": "Part 0"}, {"variables": ["select1"], "name": "Part 1"}, {"variables": ["select2"], "name": "Part 2"}], "parts": [{"layout": {"type": "all", "expression": ""}, "marks": 0, "matrix": "marks", "customMarkingAlgorithm": "", "type": "m_n_x", "showCellAnswerState": true, "minAnswers": "4", "maxAnswers": "4", "displayType": "radiogroup", "variableReplacements": [], "extendBaseMarkingAlgorithm": true, "steps": [{"scripts": {}, "marks": 0, "type": "information", "useCustomName": false, "customMarkingAlgorithm": "", "showFeedbackIcon": true, "variableReplacements": [], "extendBaseMarkingAlgorithm": true, "prompt": "

Consider the proposition:

\n

There is someone whose name is not known to the rest of the group.

\n

Using the predicate $P(m,n)$ we can express this as:

\n

$\\exists m \\forall n (\\neg P(n,m))$.

\n

To negate the proposition, we replace each $\\forall$ symbol with a $\\exists$ symbol, replace each $\\exists$ symbol with a $\\forall$ symbol, and write the negation of any statements:

\n

$\\forall m \\exists n (P(n,m))$.

\n

This corresponds to the English sentence (not asked for in this question):

\n

Everyone's name is known by somebody else.

", "customName": "", "variableReplacementStrategy": "originalfirst", "unitTests": [], "showCorrectAnswer": true}], "stepsPenalty": "0.25", "variableReplacementStrategy": "originalfirst", "minMarks": 0, "showCorrectAnswer": true, "scripts": {}, "unitTests": [], "useCustomName": false, "maxMarks": 0, "answers": ["{all[select[0]][1]}", "{all[select[1]][1]}", "{all[select[2]][1]}", "{all[select[3]][1]}"], "shuffleChoices": true, "showFeedbackIcon": true, "warningType": "warn", "choices": ["{all[select[0]][0]}", "{all[select[1]][0]}", "{all[select[2]][0]}", "{all[select[3]][0]}"], "prompt": "

If you want some help in answering this question click on Show steps. You will lose 0.25 marks as one of the questions is answered for you.

", "customName": "", "shuffleAnswers": false}, {"layout": {"type": "all", "expression": ""}, "marks": 0, "matrix": "marks", "customMarkingAlgorithm": "", "type": "m_n_x", "showCellAnswerState": true, "minAnswers": "4", "maxAnswers": "4", "displayType": "radiogroup", "variableReplacements": [], "extendBaseMarkingAlgorithm": true, "variableReplacementStrategy": "originalfirst", "minMarks": 0, "showCorrectAnswer": true, "scripts": {}, "unitTests": [], "useCustomName": false, "maxMarks": 0, "answers": ["{all[select1[0]][1]}", "{all[select1[1]][1]}", "{all[select1[2]][1]}", "{all[select1[3]][1]}"], "shuffleChoices": true, "showFeedbackIcon": true, "warningType": "warn", "choices": ["{all[select1[0]][0]}", "{all[select1[1]][0]}", "{all[select1[2]][0]}", "{all[select1[3]][0]}"], "customName": "", "shuffleAnswers": false}, {"layout": {"type": "all", "expression": ""}, "marks": 0, "matrix": "marks", "customMarkingAlgorithm": "", "type": "m_n_x", "showCellAnswerState": true, "minAnswers": "4", "maxAnswers": "4", "displayType": "radiogroup", "variableReplacements": [], "extendBaseMarkingAlgorithm": true, "variableReplacementStrategy": "originalfirst", "minMarks": 0, "showCorrectAnswer": true, "scripts": {}, "unitTests": [], "useCustomName": false, "maxMarks": 0, "answers": ["{all[select2[0]][1]}", "{all[select2[1]][1]}", "{all[select2[2]][1]}", "{all[select2[3]][1]}"], "shuffleChoices": true, "showFeedbackIcon": true, "warningType": "warn", "choices": ["{all[select2[0]][0]}", "{all[select2[1]][0]}", "{all[select2[2]][0]}", "{all[select2[3]][0]}"], "customName": "", "shuffleAnswers": false}], "metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": "

English sentences which are propositions are given and the appropriate logical expression chosen for the negation of the sentence.

"}, "functions": {}, "preamble": {"css": "", "js": ""}, "variablesTest": {"condition": "", "maxRuns": 100}, "name": "Daniel's copy of Quantifiers 3-", "rulesets": {}, "tags": [], "statement": "

In a seminar group, for group members $m$ and $n$, we let $P(m,n)$  be the predicate m knows the name of n .

\n

Negate each of the following English sentences and choose the corresponding expression for the negated proposition involving quantifiers.

\n

Note that marks are deducted for each incorrect choice. However, the minimum mark is $0$.

", "variables": {"select2": {"description": "", "definition": "list(set(0..length(all)-1)-(set(select) or set(select1)))", "name": "select2", "templateType": "anything", "group": "Part 2"}, "select": {"description": "", "definition": "shuffle(list(0..length(all)-1))[0..4]", "name": "select", "templateType": "anything", "group": "Part 0"}, "marks": {"description": "", "definition": "list(0.5id(4)-0.25matrix(repeat(repeat(1,4),4)))", "name": "marks", "templateType": "anything", "group": "Ungrouped variables"}, "all": {"description": "", "definition": "[['There is someone whose name is not known to the rest of the group.',\n '$\\\\forall m \\\\exists n (P(n,m))$',\n 'Everybody\\'s name is known by at least one other person.',\n '$\\\\exists m \\\\forall n (\\\\neg P(n,m))$'],\n ['Every group member doesn\\'t know the name of at least one other.',\n '$\\\\exists m \\\\forall n ( P(m,n))$',\n 'Somebody knows the name of everybody.',\n ' $\\\\forall m \\\\exists n (\\\\neg P(m,n))$'],\n ['Nobody knows the name of anybody else.',\n '$\\\\exists m \\\\exists n (P(m,n))$',\n 'At least one person knows the name of another.',\n '$\\\\forall m \\\\forall n (\\\\neg P(m,n))$'],\n ['There is a pair of group members who do not know each other\\'s name.',\n '$\\\\forall m \\\\forall n (P(m,n) \\\\lor P(n,m))$',\n 'Given any pair of members, then at least one of them knows the name of the other.',\n '$\\\\exists m \\\\exists n (\\\\neg P(m,n) \\\\land \\\\neg P(n,m)$'],\n ['There is someone who knows everyone\\'s name.',\n '$\\\\forall m \\\\exists n (\\\\neg P(m,n))$',\n 'Everybody doesn\\'t know the name of at least one other.',\n '$\\\\exists m \\\\forall n (P(m,n))$'],\n ['There is at least one person who knows the name of somebody else.',\n '$\\\\forall m \\\\forall n ( \\\\neg P(n,m))$',\n 'Nobody knows the name of anyone else.',\n '$\\\\exists m \\\\exists n (P(n,m))$'],\n ['There is someone who doesn\\'t know the name of at least one other group member.',\n '$\\\\forall m \\\\forall n (P(n,m))$',\n 'Everybody knows everybody else\\'s names.',\n '$\\\\exists m \\\\exists n (\\\\neg P(n,m))$'],\n ['Someone\\'s name is known to everyone else.',\n '$\\\\forall m \\\\exists n ( \\\\neg P(n,m))$',\n 'Everybody\\'s name is not known by at least one other person.',\n '$\\\\exists m \\\\forall n ( P(n,m))$'],\n ['There is at least one person who does not know the name of anybody else.',\n '$\\\\forall m \\\\exists n ( P(m,n))$',\n 'Everybody knows the name of at least one other.',\n '$\\\\exists m \\\\forall n (\\\\neg P(m,n))$'],\n ['Everybody knows at least one other person\\'s name.',\n '$\\\\exists m \\\\forall n (\\\\neg P(m,n))$',\n 'There is somebody who does not know anyone else\\'s name.',\n '$\\\\forall m \\\\exists n (P(m,n))$'],\n ['Any member of the group has at least one person who doesn\\'t know their name.',\n '$\\\\exists n \\\\forall m (P(m,n))$',\n 'There is someone whose name is known by everyone.',\n '$\\\\forall n \\\\exists m (\\\\neg P(m,n))$'],\n ['There are at least two people who know each other\\'s name.',\n '$\\\\forall n \\\\forall m (\\\\neg P(n,m) \\\\lor \\\\neg P(m,n))$',\n 'For any two people in the group at least one doesn\\'t know the name of the other.',\n '$\\\\exists n \\\\exists m (P(n,m) \\\\land P(m,n))$']\n \n ]", "name": "all", "templateType": "anything", "group": "Ungrouped variables"}, "select1": {"description": "", "definition": "list(set(0..length(all)-1)-set(select))[0..4]", "name": "select1", "templateType": "anything", "group": "Part 1"}}, "advice": "

In the following we use the rules for negating a proposition involving predicates and quantifiers as given in the lectures.

\n

a) 

\n

1. The sentence:

\n

 {all[select[0]][0]} 

\n

can be written in predicate form with quantifiers as:

\n

  {all[select[0]][3]}

\n

The negation of the sentence can be written as:

\n

 {all[select[0]][2]} 

\n

The predicate form with quantifiers for this is:

\n

 {all[select[0]][1]}

\n

\n

2. The sentence:

\n

 {all[select[1]][0]} 

\n

can be written in predicate form with quantifiers as:

\n

  {all[select[1]][3]}

\n

The negation of the sentence can be written as:

\n

 {all[select[1]][2]} 

\n

The predicate form with quantifiers for this is:

\n

 {all[select[1]][1]}

\n

\n

3. The sentence:

\n

 {all[select[2]][0]} 

\n

can be written in predicate form with quantifiers as:

\n

  {all[select[2]][3]}

\n

The negation of the sentence can be written as:

\n

 {all[select[2]][2]} 

\n

The predicate form with quantifiers for this is:

\n

 {all[select[2]][1]}

\n

\n

4. The sentence:

\n

 {all[select[3]][0]} 

\n

can be written in predicate form with quantifiers as:

\n

  {all[select[3]][3]}

\n

The negation of the sentence can be written as:

\n

 {all[select[3]][2]} 

\n

The predicate form with quantifiers for this is:

\n

 {all[select[3]][1]}

\n

Similarly for Parts b) and c).

\n

", "extensions": [], "ungrouped_variables": ["all", "marks"], "contributors": [{"name": "Daniel Mansfield", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/743/"}, {"name": "Sean Gardiner", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2443/"}]}]}], "contributors": [{"name": "Daniel Mansfield", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/743/"}, {"name": "Sean Gardiner", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2443/"}]}